Belt-gearing.



W. J. BAYRER.

BELT GEARING.

APPLICATION FILED DEC.18. I916. 1,259,343. I 1 Patented Max-.12, 1918.

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W. J. BAYREH.

BELT GEARING.

APPLICATION FILED use. 18, 1916.

Patented Mar. 12, 1918.

. 2 m lw lw m ma ww 6 a STATES P1 WILLIAM J. BAYRER, OF HARTFORD, CONNECTICUT.

BELT-GEARING.

To all whom it may concern:

Be it known that I,WILLIAM J. BAYRER, of Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Belt-Gearing, of which the following is a specification.

This invention relates tobelt gearing especially suitable for drilling machines of the well known type wherein a longitudinally movable tool carrying spindle is arranged to be rotated at various speeds best adapted for drilling holes of sizes within the range of its capacity.

The object of the invention is the provision of generally simplified belt controlling 'device for a machine of this type possessing features of novelty cooperative to effect increased efliciency of operation and adapted for comparatively inexpensive manufacture. These features are fully set forth in the following detailed description of the embodiment of the invention which has been selected for illustration in the accompanying drawings. The scope of my invention, it will be understood, is not however, limited to the exact showing of the drawings but is defined by the appended claims.

In the drawings,

Figure 1, is a side view of the upper part of a drilling machine constructed in accordance with my invention.

Fig. 2, is a side view partly in section, of the lower part of the machine shown in Fig. 1. and shows certain mechanism supported thereby.

Fig. 3, is a rear view of the parts shown in Fig. 2.

Fig. 4;"is a view partly in section of the ,tool spindle and its longitudinally movable supporting sleeve.

Fig. 5, 1s a view partly in section of spin dle driving means.

Fig. 6, is a sectional detail view of lubrieating devices assocnated with the bearings shown in Fig. 5.

Fig. 7, is a view partly in section of idler or guide pulleys and their supporting means.

Fig. 8, is aldetail view of a crank and certain parts associated therewith for posiv tioning the guide pulley support.

- Fig. 9, is a sectional view on line 99 of Fig. 8.

Fig. 10, is a plan view partlyin section of the guide pulleys and their supporting means.

Fig. 11, is a sectional view on line 11-11 of Fig. 10. I

Fig. '12, is a sectional view through the hub of one of the guide pulleys and the yoke by which it is carried.

Fig. 13, is a view partly in sectionof high speed mechanism attachable to the spindle sleeve and operable from the spindle.

Fig. 14, is a sectional view on line 1414 of Fig, 2, and,

Figs. 15 and 16, are detail views hereinafter more fully described.

Like characters of reference designate like parts throughout the several views. The scale to which the drawings are made it will be noted is not the same in all of the views.

Referring to the drawings the general construction of the machine shown therein will be readily understood if briefly described as follows -The machine frame consists of the base 2, and pillar 3. At the front of the base, ways 4, are provided to receive the work support or table 5, which is movable along the ways by any suitable means, as a screw, (not shown). Brackets 6, and 7, secured respectively to opposite sides of the base. support the driving shaft 8, and parts associated therewith which will be hereinafter described. Secured to ways 9. at the front of pillar 3, are brackets 10 and 11,

. which respectively support the spindle driving pulley 12. and the sleeve 13,'the latter being longitudinally movable together with the spindle 14, which is rotatably held by the sleeve. The weight of the spindle and the sleeve is counterbalanced by the weight 15, which hangs within the hollow base at one end of a cable or chain 16. which is passed over pulleys 17 and 18. and secured at its other end to sleeve 13. This arrangement permits movementof the sleeve and spindle to be effected with ease. as through rack and pinion mechanism including rack 20, pinion 21. and the manually operable lever 22, which provides in a usual and obvious manner for control of the feed of a tool carried by the spindle. At the rear of pillar 3, are ways 23, for anidler or guide pulley support 24, movable vertically by means Specification of Letters Patent. Patented Mar, 12, 1918. 1 Application filed December 18, 1916. Serial No. 137,655.

hereinafter described to permit positioning of the ide pulleys in relation to different steps the spindle driving cone pulley 12.

The various parts of the drilling machine as thus far described are not new, and their described general arrangement is not new, but my invention resides in construction associatedwith that set forth, and the result ing features of novelty will now be described in detail.

Near each end of sleeve 13, an annular ball bearing supports the spindle l4, and at one end a thrust ball bearing is associated with the annular hearing. The ball race members of the thrust bearing are designated by 25 and 26, the latter having a hub 27, upon which is sleeved the former, with space between the members adapted to receive balls 28, in a suitable manner. The hub 27 is extended along the spindle beyond the member 25 to form the inner ring 29, of the annular bearing whose outer ring and balls are designated respectively by 30, and 31. The member 25 and ring 30 are preferably snugly fitted Within a counterbored end 32, of sleeve 13, so that they remain stationary while member 26 rotates with the spindle. The race for balls 31 is adapted to retain fluid lubricant for quite a prolonged period. In order to also efi'ect retention of lubricant for the balls 28, a comparatively thin metal cap 33, is held between a collar 34, on the spindle, and bearing member 26, with the flange or wall of the counterbore extending over the reduced periphery of bearing member 25. At the upper end of sleeve 13, a counterbore is formed to non-rotatively receive the member 35, of an annular bearingwhich is further made up of balls 36, and member 37, the latter being secured to rotate with the spindle, but movable longitudinally thereof for a purpose that will presently appear. Pinned to the spindle adjacent to bearing member 37, is a collar 38, bored to receive several springs as 39, which are adapted to bear against said member 37.

Obviously these springs tend to yieldingly thrust member 37 into contactwith balls 36 and to draw the spindle bearings at the op posite endof the sleeve into suitable relation, which relation will be properly maintained irrespective of changes in length of spindle due to expansion and contraction under varying temperature.

The spindle driving pulley 12, is secured to sleeve 40, which latter is supported near its ends in the bracket 10, by annular ball bearings 41 and 42., Bearing 41 is made up of inner ring 43, balls 44, and outer ring 45. The inner ring together with a lubricant conveyer 46, is held between a head 47, at

I one end of sleeve 40, and the end of pulley hub 48, .while the outer ring 45, surrounded by the flange 49, of lubricant container 50, is received y a counterbore 51, in bracket 10, wherein said ring and container are lubricant expelled from the groove of the conveyer by centrifugal force will be diverted by the inclined wall 58, to the ball race, thereby insuring ample lubrication for the bearing. In a like manner the bearing 42, is provided with a lubricating device which need not be described in detail as it is a counterpart of the one associated with bearing 41. It will be noted that the sleeve 40 and the pulley secured thereto are held in proper relation to the bearings by the nut 60, which is threaded on to that end of the sleeve opposite to the head 47. Rotary movement of the pulley and sleeve are transmitted to the spindle through oppositely disposed keys 61 and 62, which engage respective splines or keyWays in the spindle. These keys are accommodated in the sleeve head 47 where they are held by screws 63. As said head extends below the bracket opening therefor, a protective cap as 64, may be secured to the bracket. Also the counterbores for the ball bearings may be provided with suitable caps as 65 and 66, to exclude dust, etc.

Referring to Figs. 7, 8, and 9, the guide pulley support and positioning means therefor will now be described. It will of course be understood that the guide pulleys are adjustable into different planes correspond-- ing to the steps of the cone pulley 12, in

As the latter rotates with the spindle it follows that order that the belt 70, may be best guided to the respective steps,also to compensate for the difference in diameter of the steps,

the pulleys are pivotally adjustable as will more fully appear.

Between the ways 23, already briefly mentioned, there are two separate bearings 1, and 72, which as shown, may be formed 1ntegral 'with the pillar 3. These bearings which are axially alined in parallelism with the Ways 23, slidably receive a rod 74, rigidly secured in a lug 7 5, which projects from the guide pulley support. This arrangement serves to hold said support'properly on its ways in a manner to permit of its adjustment thereon. Mechanism for effecting such adjustment includes a rack and pinion. Rack teeth '76, are formed at one end of rod 74, and these teeth are engaged by the pinion 77, formedupon the reduced part of a shaft 78, which is supported in a bore 79, extending transversely of and intersecting the bearing 71. The reduced end '80, of shaft 78, projects through the machine frame and is provided with a retaining collar 81. At its Opposite end said shaft extends through and beyonda hub 82, and is squared at 84, to receive a crank or handle 85,'whichis split and provided with a clamping screw 86. Crank 85 is formed with a lug 87, bored to receive a latch bolt 88, backed by a spring 89. A pin 90, carried by the latch bolt projects through a slot 92, and serves as a latch manipulat-ingknob and also as a stop coacting with an end wall of the slot to limit outward movement of the latch bolt. It will be obvious that gravity acting upon the support 24, exerts through the rack and pinion'mechanism, a tendency to rotate shaft 78, to ether with crank 85. This tendency is reslsted by engagement of latch bolt 88, with a shoulder 93, on the cam-shaped periphery of, hub 82,

said hub and latch bolt comprising a single tooth ratchet device easily operable to effect the required definite positioning of support 21, by virtue of the fact that the pinion is proportioned so that one turn thereof will raise or'lower the guide pulley support a distance corresponding to that between adjacent steps of the cone pulley 12. It follows that for each turn of the crank, the guide pulleys are raised or lowered, according to the direction in which the crank is turned, a distance corresponding to that between adjacent steps of the cone pulley, and engagement of the latch bolt with the shoulder 93, exactly defines the proper positions of the guide pulleys for respective steps of the cone pulley, In order that an operator,

may at a glance, ascertain for which particular step of the cone pulley the guide pulleys are located, there may be employed an index plat-e as 94. This is marked with numbers corresponding to the cone pulley steps and is secured to one of the Ways 23, (see Figs. 1, and 16). An index pointer 95, is carried by the guide pulley support 24:, and, for the four steps of the cone pulley, beginning with the step of largest diameter, is arranged to register at 1, 2, 3, and 4 respectively. The pointer is secured to support 24, by screws passing through elongated slots in its base so that when the parts are assembled said pointer may be adjusted to exactly register with the numbers on th index plate.

The guide pulley support is provided with 'ways 96, to receive a slide 97, upon which are pivotally mounted the guide pulleys 98, and 99 (see Figs. 7, 10, and 11). As shown the outer guide pulley, that designated by 98, is of the flanged type and is held to swing about an axis extending in a trend of the belt passing thereover.

plane considerably oflset from a parallel plane coincident with the axis about which the pulley rotates, from which fact it will be clear that thepu-lleyis'adapted to freely and automatically accommodate itself to ltfie e pivotal arrangement involved may be of any suitable construction, but I prefer to employ oppositely disposed round pointed screws as 100, threaded into the bracketed end 101, of slide 97, and properly secured by set screws. The round points of the pivot screws engage appropriate sockets 102, and 103, in arm 104, which is laterally extended from the foot of the pulley yoke 105, said arm being provided with an opening 106, for passage, of the belt. Directly beneath the pulley, yoke 105, is provided with two sets of lugs, each of which supports a pin bearing an anti-friction roller,

the pins and rollers being respectively designated by 108 and 109, and 110 and 111, (see Fig. 15). Said rollers track upon a crossbar of slide 97 and afford ample support to prevent cramping of the yoke under influence of the belt pull. From the foregoing description it will be apparent that what may be termed the angular adjustment of pulley 98 is at all times automatically sensitive to requirements of the belt, and, for this pulley, the changes thus effected by passage of the belt from different steps of the cone pulley are quite desirable; for the in ner guide pulley, however, a single angular adjustmentmay satisfactorily serve to guide the belt to any of the cone pulley steps. Due to this fact the yoke 115, for pulley 98,

' may be provided with a hub 116. bored to able, and when efi'ected may be maintained by'means of the set screw, 119.

Fig. 12, illustrates the method I prefer to employ for mounting pulley 98 iniits yoke, and as pulley 99 is mounted in the same manner a description of the mounting for pulley 98 will suffice for both. Said pulley is supported between oppositely disposed arms 120, and 121, of the yoke 105, on a pair of annular ball bearings 122, and 123, the outer rings 124, and 125, of which arefirmly secured in counterbores in the ends of the pulley hub together with flanged disks 126, and 127, which also rotate with the pulley. The inner rings 128, and 129, of the ball bearings are sleeved upon a shaft or bolt 130, together with spacing collars 131, and 132. The shaft at one end is .mainta'ined yset screw'135p The disks 126,

. and 127, are: centrally perforated to accommodate the shaft but they extend far enough overthe ball racesso-that a sufiicient =quan-.

titylof suitable fluidmay be retained. within the hub of the pulleyto submergea por lubrication, 5 t

, Theforetgoing description of certain ad- .justments' .tion of ,said races, thus insuring adequate alinement .of the pulleys. is obtained with'reto another. It involves movement of slide 97, toward or vfrom the. tool-spindle as may be required but ,invnoway' interferes with the pulley-falin'ement mentioned Mechanism for moving. the slide'is supported by abra'cket'138, secured to one sidelofpulley support 24, (see Fig. 10). Within a housing 139, formed integral with-the bracket,

there is mounted on the stud shaft 140, a combined spur and worm gear wheel 141, the spur gear teeth 142, of which mesh with .a rack 143, secured to slide 97, while the worm gear teeth engage the worm 144. The latter is integral with a shaft'145, extending through bearings 146, and 147, of bracket 138. A part 148, of the shaft,.which extends through bearing 146, is slightly reduced to 40 form a shoulder at 149, and is provided at the outer end with a collar 150, secured by a set screw. The length of the shaft between collar 150 and shoulder 149' is greater than the lengthof bearing 146, so that it ispos sible to impart to the shaft a certain amount of longitudinal movement and it is obvious that when so moved, as in the direction of the arrow A, the wormis efi'ective as a rack, by reason of which, it transmits motion through gear 141, rack 143., and slide 97, to move the guide ulleys in a direction to tighten the belt, eversely stated, the

. belt pulltends through slide 97, rack 14-3, gear 141, and worm 144, to move the shaft longitudinally in a direction opposite to that indicated by the' arrow. The means I prefer to employ for effecting an endwise thrust of the shaft in opposition to that created by the belt pull, comprises a spring 151, surrounding the shaft between collar 152, and bearing147, said spring being provided at its ends with hardenedwashers and inclos'ed by a tubular extension 153, of hearing 147 Consideringnow the rotary movementof shaft 140, 'efiect which it has seor" which the vguide pulleys are adapted setsforth the'mannerin which the for longitudinally moving shaft 170, to actucured to the forward end thereof a hand wheel 154, it will be apparent that when from subjecting'the belt to excessive and injurious tension. Furthermore such stop means providean indicator whereby an op'-" erator can'quicklyand easily determine'the ,1 spect to thedifi'erentsteps ofthe' cone pul-'- eley, A further adjustment of the guide pul- 20 ,leys is, employed. fer, tensioning. the belt in 1 accordance with requirements when thebelt= is shifted fromone step-of the vcone pulley most efi'ecti've tensionyfor the belt. As shown, stop means for'the purpose set forth, "comprise a pin 160 projecting from'a lug at the outer "end oftubular extension 153', and a in* 161, carried by the collar-152.

Wheny turnin'g the shaft it is advanced against the tension of the spring to such an extent that P111161, engages pin 160, the

maximum orsuitable tension has been.

and it cannot be fur and 165, to receive the usual shiftable belt,

(not shown). A belt shifting device is mounted on the shaft 17 0, which is supported in the bearings 171, and 172, de ending respectively from brackets 6 and The belt shifting device comprises a ring 173, secured near one end ofshaft170, and a yoke 174, ad'ustably secured to the ring. Peripheral a justment of the yoke thus afforded, permits accommodation of the belt for any angle at which it may be directed for engagement with the pulleys. Means ate the belt shifting device will now be described.

Supported in bearings 176', 177, and 178,

. of the machine base, is a shaft 179, provided at its outer end toward the front of the machinewith a foot lever 180, and at its other end with the segment 181. This segment has an offset portion 182, slotted at'183, to

of the bearings for shaft 17 9-, to receive' thrust of the gearing, the latter method being obviously much more costly as it would 130 involve considerable handling of the large base casting. Secured to the upper end of the rock shaft is a crank or lever 190, connected by a link 191, with a collar 192, fast on shaft 170. The crank 190, through'described parts, may be moved by the foot lever in either direction about a half revolution or a-dis'tance governed by the length of slot 183, and the motion thus imparted is just suificient to move the belt yoke to shift the belt from one of the tight and loose pul-' le S to the. other.

Vhile the shaft 8, may be supported in any suitable manner, I prefer to employ in each of the brackets 6, and 7 an annular ball bearing like that indicated in a general way by 195. (See Fig. 14.) The inner member of this hearing is held on a slightly reduced part 196, of shaft 8, by the nut 197. The outer member together with a peripherally flanged lubricant retainingdisk 198, is clamped in the split bearing of its respective bracket. The flange 199, of disk 198, extends beyond the opposite side of the bearing and is spun over a complemental lubricant retaining disk 200. The disks are of course perforated to accommodate the shaft but they overlie the ball race so that a sulficient amount of lubricant is retained at the lower part of the bearing to insure its thorough lubrication.

The four spindle speeds obtainable through mechanism of the drilling machine hereinbefore described, may, by the addition of other simple mechanism, designated in a general way by 210, be converted into four different speeds for a su plemental tool carrier or spindle. (See Figs. 1 and 13.) The additional mechanism includes drivin elements as the flanged pulleys 211-, an 212,

and the driven elements, as the flanged pul ley 213, and pulley 214, the latter comprising an enlarged portion of the supplemental tool chuck carrier or spindle 215. The pulley 211, is secured to and rotates with the main spindle 14; pulley 214, is supported on an arbor 216, having a taper shank to fit the usual socket with which drill spindles are provided. Annular ball bearings are fitted within the pulley 214, and upon its arbor. They are held in position by a head on the arbor, the spacing collar 217, and a cap 218, the latter being threaded into one end of the pulley. A thrust bearing comprising ball 219, engaging hardened washers held in sockets respectively in the arbor and the tool carrier, is provided to resist thrust developed when a tool in the carrier engages its work. It will be noted that the bearings just described are so inclosed as to be well adapted for the lubrication desirable for extremely high speeds. Pulleys-212, and 213, are integrally connected by an elongated hub 220, and mounted in axial parallelism with spindle 14, on a shaft 221. Said shaft at one end is provided with'a head 222, to engage the inner ring of anannular ball bearing 223, mounted thereon. The inner ringof another annular ball bearing 224, is also mounted on the shaft and Spaced from the other bearing by an elongated collar 225,

the pulley hub isfitted at its ends with suit-' able caps as 230, and 231. Shaft support 227, is adjustably secured to a shank 232, of

the split collar 233, which may be clamped to the spindle feeding sleeve by a screw as 234. By adjustment of shaft support 227, along the collar shank, a suitable tension may be effected for the belts 240, and 241, said belts being provided to transmit moa suitable position it may be secured against displacement by set screw 242. l

Inasmuch as the speed converting mech anism set forth is entirely supported by sleeve 13, it follows that feeding of the tool driven thereby may be accomplished in the same manner and bythe-same mechanism as that of a-tool carried by the spindle proper. Furthermore this method of attaching the speed converting, mechanism requires nothing in the Way of bosses, brackets or the like, in permanent association with the rest of the machine.

- Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a drilling machine, in combination, a spindle driving cone pulley, a pair of guide pulleys, a support for the guide pulleys movably mounted on the machine frame and shiftable to place the guide pulleys into a different and definite position for each step of the conepulley, a stop device for indicating said positions, and means for releasing the stop device.

2. In a drilling machine, in combination, a spindle driving cone pulley, a pair, of guide pulleys, a supportv for the guide pulleys, mounted on ways of the machine frame, a rack associated with the support, a shaft extending through the machine frame and provided with a pinion in engagement with the rack, a hub having a stop shoulder adjacent one end of the shaft, a crank secured to the shaft, and a latch carried by the crank, said latch being cooperative with tion from the driving to the driven elements descr1bed.- When the support is adjusted to 1o for-each stepof the tone pulley, astop device for 'maintain'ingany one of. said po-sig tions; and registering means for indicating whichko-f said positions may have been tablished;

a spindle-driving cone pulley, a pair of guide pulleys, ,a' support for the guide pulleys, ways-onthe machine frame to re ceive=*th'e s'upport,lmeans for iniovin'g the I support to 'difler'ently-and definltely posb tion f the guide pulleys with' respect to the a cone pulley, and indexing means for" indicatingthedifi'erent positions to which the.

guide-pulleys are movable, said'mea'ns" in- :5 veluding an index platea'ndgan'index pointer,

one of which is'secured to the'inac'hine frame and the other to' the guide pulleysupport' 5. In a drillin machine, in'combination, a support, a sli e carried by the'support,

g pulleys mounted on the slide for guiding a belt, means for applyinga yielding pressure i against the'slide tending to move it together with the pulleys in a direction to tension the belt, and means for limiting the pressure thus applied.

6. In a drillin machine, in combination,

a support, a sli e carried by the support,

pulleys mounted on the slide for guiding a. belt, a shaft carried by the support and 40 adapted for endwise and rotary movement,

a gear element interposed between the shaft and the slide having gear teeth in mesh with rack teeth on the slide and worm teeth in mesh with a worm thread on the shaft, and

a spring surrounding the'shaftbetween a collar onthe latter and a part of the support whereby tension of the spring is opposed by the belt through endwise movement of the shaft and whereby rotary movelo ment of the shaft changes the degree of'the opposing forces.

7 In a drilling machine, in combination, a support, a slide, ulleys carried by the slide and movable t erewith to ,tenslo'n'a l5 belt, a shaft mounted in bearings of the sup-\- port for longitudinal and rotary movement' with respect thereto, means for effecting a longitudinal thrust upon the shaft, ma

means interposed between the slide and the C0 shaft, whereby the thrust upon the shaft will oppose the thrust upon the slide due to the effect of thebelt. 8. In a drilling machine, in combination-3;,

a support, a slide, pulleys carried by the .6 slide and movable therewith tension a 4; In a drilling machine, in combination,

belt, a shaft mounted in bearings of the support for longitudinal and rotary movement with respect thereto, a gear element interpose'd between the slide .and the shaft' having gear teeth in mesh with-rack teeth on the slide and wormteeth in mesh with a Wormthread on the. shaft, a collar on the shaft, and a spring interposed between the i collar and one of the shaft bearingsto ope pose thrust transmitted; through associated, parts by thefbelt tension, 1

a support, a slide, pulleys 9. In a drillinggma h'ne', coinbin ation,

carried by, the slide and movable therewith to tension I belt, a s'haft"mount'ed in 'beari ngs of the j support for longitudmal and rotary move-g, I

ment'with respect thereto,,a sprin [:for exand theshaft' having gear teeth in mesh with erting'a longitudinal thrust-upont e shaft,

a gear element interposed between the slide,

rack teeth on the slide and worm teeth in y "mesh with a worm thread on. the, sha ft, -Y "whereby 'the.' 'thrust of the spring is transx mitted through'associated parts to tension,

the belt and whereby rotary movement of the shaft efiects'a change in the tension ex 'erted by the spring. i ,4

10. In a drillin 'machine, incombination,

a support, a, sli e, pulleys carried by the slide and movable therewith to tension a belt, a shaft mounted in bearings of the support for longitudinal and rotary movement with respect thereto, means for exerting a longitudinal thrust upon the shaft,

and means interposed between the slide and the shaft whereby the thrust imparted to the shaft is transmitted through associated parts to tension the belt and whereby rotary movement of the shaft effects a change in the degree of tension exerted.

11. Belt gearing including in combination,

a support, a slide, pulleys carried by the slide, means for imparting a thrust to the slide to tension .a belt engaged by the pulleys, and an element associated with said means movable to transmit the thrust to the slide and also movable to, vary the degree of thrust transmitted.

12. Belt gearin including in combination,

a support, a sli e, pulleys carried by the slide, means for imparting. a thrust to the slide" to tension a belt engaged by the pulleys, and an element associated with said means and arranged for movements of different-character, said movements being effective respectively" for transmitting thrust to the slide and to vary the degree of thrust transmited.

13. In a drilling machine, in combination, 7

a slide, a pulley for guiding a belt, a carrier for the pulley comprising a yoke with an angularly extended shank, said carrier near the juncture of its yoke and shank being adapted to engage the slide, and aipivotal connection between the slide and carrier near the end of the carrier shank, said connection including oppositely disposed adjustable pivots whereby. thecarriermay be suitably alined with respect to its engagement with the slide.

'14.- Belt gearing including in combination,

guide pulleys, a support for the guide pul,

leys movably mounted on the machine frame and shiftable to place the guide pulleys into a different and definite position for each step of the cone pulley, and means for indicating the different positions to which the guide pulleys are movable.

16. Belt gearing for drilling machines including in combination a driving shaft and a driven shaft extending in difierent directions, a single pulley on one of the shafts and a plurality of pulleys on the other shaft, idler. pulleys for directing a belt from the single pulley to any one of the other pulleys,

means for moving the idler pulleys into position for guiding a belt from the single guide pulleys, a support for the guide pulleys mounted on Ways of the machine frame, a rack associated with the support, a shaft extending through the machine frame and provided with a pinion in engagement with the rack, and ratchet means associated with the shaft and machine frame for holding the guide pulleys in different and definite positions with r espect to'the cone pulley.

'18. In a drilling machine, in combination,

a spindle driving cone pulley, a slide, a pair of pulleys carried by the slide for guiding a belt, a support for the slide movably mounted on the machine frame and shiftable to ,place the guide pulleys into a different position for each step of the cone pulley, means for applying a yielding pressure against the slide tending to move it together With the guide pulleys in a direction to tension the belt, and mechanism for effecting a degree of yielding pressure against the slide suitable for each step of the cone pulley.

In testimony whereof I have alfixed my signature, in presence of two Witnesses.

' 'WILLIAM J. BAYRER. 'Witnesses:

HOMER H. BAYRER. F. E. ANDERSON. 

